Using the Automatic Weather Station data to understand weather and rainfall (in this case, of Kalimpong)

The rainfall chart for the period May2025 to May2026 for Kalimpong is above and a brief analysis of the same here👇:
a. We had a fairly wet monsoon season (from approx May to Oct2025) characterized by 9 spikes when rainfall exceeded 90mm in a 24hr period. The season did start with some hiccups though:

Typical cloud image over North Bengal and Sikkim before the heavy rain of 19Jun2025

Warning on 13Jul2025 for the heavy rain (112.8mm) on 14Jul2025.

July is typically the wettest month of the monsoon season. In July 2025, there were four days during which rainfall exceeded 90 mm in a 24-hour period. Thereafter, rainfall gradually declined, apart from a brief spike on 12 August 2025. Total rainfall amounted to 467 mm in August and 253.2 mm in September 2025.

October 2025 was relatively dry, except for two days of intense rainfall. On 4–5 October, widespread heavy rain affected the entire region and triggered devastating landslides and flash floods, resulting in significant loss of life in Mirik.

These instances of spikes in rainfall are normally associated with convective clouds and normally consist of short, violent bursts of rainfall which cause high runoff and low infiltration of water (as such no recharge of aquifers) and only result in soil erosion, landslides and damage to roads.

 

After the 2025 monsoons, we went thru an extended 5 month period of drought-like conditions from November2025 to March2026.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744 

8 Davis AWS stations are available in the Darjeeling Sikkim Himalaya - a brief tutorial on using the AWS.

Kindly refer STH blog of 21Nov2025 on the same subject 

Ever since two Davis Automatic Weather Stations were installed in Kalimpong under Project SHAMROCC in March 2016, I have consistently advocated for expanding the use of automatic weather stations across our region. In the Himalayas, where weather conditions can shift rapidly and the impacts of climate change are especially pronounced, timely and localized data is not a luxury—it is essential. Here, I am glad to inform you that as of now, we have 8 AWS in our vicinity from which updated weather inputs are available 24X7.

Against this backdrop, it is concerning that the extensive AWS network maintained by the India Meteorological Department (IMD), which was previously accessible to the public, has been taken off open access since around March 2025 and now requires login credentials.

AWS can transform how we understand and respond to weather in fragile mountain ecosystems. These systems automatically record and transmit real-time weather data without the need for human intervention.
In the Himalayas, where terrain is rugged and access is limited, AWS are indispensable. They provide continuous, high-accuracy data from remote locations, filling critical gaps left by traditional observation methods. This is especially important as climate change accelerates shifts in weather patterns, glacier melt, and extreme events.
AWS also play a key role in strengthening early warning systems and can help map changing rainfall patterns. 

For those interested in using the global Davis AWS system, here is quick tutorial:

1. Install the Weatherlink Mobile app from Google Playstore. You may have to create an account and register.
2. Open the app and add stations by hitting the + sign in the top left hand corner. Here searching by place names gives satisfactory results 
eg searching for 'Kurseong' will give 'STH KURSEONG NEW' result.
Touch the flag icon on the left to confirm adding the station - it will turn GREEN.
3. In our vicinity, you can add the following 8 stations:
a. Kalimpong - for 'STH AWS' (operated by SaveTheHIlls).
b. Kurseong - for 'STH KURSEONG NEW' (operated by SaveTheHIlls).
c. Ahalay - for 'AHALAY GBN AWS' (operated by Govt of WB, in Gorubathan).
d. Darjeeling - for 'ST PAUL'S SCHOOL METEOROLOGICAL STATION' (operated by SPS, Darjeeling).
e. Pedong - for 'BSA AWS-PEDONG' (operated by Bal Suraksha Abhiyan, Kalimpong).
f. Todey - for 'BSA AWS, TODEY, KALIMPONG' - (operated by Bal Suraksha Abhiyan, Kalimpong) - Todey is located in the eastern most corner of Kalimpong district, close to Bhutan.
g. Gangtok - for 'LAMA BUILDING' (privately operated).
h. Gangtok - for 'SSDMASEEDS' (operated by Sikkim Govt).
4. Your phone display should look something like this👇

Do experiment with the various features which are on the app to receive updated weather information from the DAVIS AWS located in our area as well as all over the world.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

About Early Warning Devices viz Doppler Weather Radars (DWRs) and Automatic Weather Stations (AWS)

  

Below is an article from today’s The Statesman that underscores many of the key issues we at 'SaveTheHills' (STH) have been tirelessly raising, writing about, and advocating for over many years:

 

The information about DWRs which I have been able to garner from the internet is as under:

 

As per the above information there are 10 DWRs in the Western Himalayas (RED dots) and ONLY 3 DWRs in the Eastern region (GREEN dots). In this connection, there maybe some conventional (non DWR) older type weather radars about which I could not get information. These will be replaced by DWRs by 2026.
The above information is reproduced below in a map form:

 

Many years ago, I attended an IMD workshop at Baluatar in Gangtok, where I raised the need of a DWR in the Darjeeling-Sikkim Himalayas. I was told that then that a DWR had been earmarked for Sikkim by IMD but as can be seen nothing materialized over the years and now a DWR is being installed in Malda (W Bengal) which will certainly give adequate inputs/warning for North Bengal but may not be effective for the mountainous regions because of signal loss and shadowing.
In this regard, Nepal has 3 weather radars but I could not locate their data and Bhutan has none.
About IMD Automatic Weather Station website
I have already partly covered this in my blog of yesterday but if you try and access the IMD AWS site (http://aws.imd.gov.in:8091/internal/login.php) today, you will be greeted with this sign

 

Whereas just a few months ago, the IMD AWS information for the whole country was freely available for anyone, now it is 'internal information' only available to IMD or government officials.
Each state has a separate password to gain access to weather data of the state.

With the inputs which I have given you, please read 'The Statesman' article again and wonder which direction our early warning systems for the mountains are pointing.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

Importance of real-time weather information in hydrological disasters: Need for more AWS

We, at SaveTheHills have long realized the importance of real-time weather inputs especially in the Himalayas where weather can change quickly and with devastating consequences.
In this regard, 'Hazard Alerts', our WhatsApp based social media group in this region, does precisely that - disburse verified information on weather and updates on forecast heavy rain, hazards such as landslides, road closures to the community in the quickest time and I am extremely happy to state that all three WhatsApp groups (Hazard Alerts 1,2, 3) and our other social media handles in Instagram, FB and so on, have today emerged as disciplined, powerful community driven platforms, which share such information and help each other using reports from individual members, satellite images of clouding, lightning app reports, social media posts and so on.

STH has also encouraged and helped in establishing a network of online AWS in this region so that real-time information from these stations is available to the community as well as disaster management people of this region:

I was keeping a track of Hurricane 'Milton' recently, and was able to monitor the rainfall data of several places around Tampa , Florida from my home in the Himalayan foothills as the storm wreaked havoc there. I accessed the weather in real-time on the Weatherlink app for Davis automatic weather stations in the area.

It is amazing to see how powerful technology is these days and I was particularly impressed to see the density of DAVIS AWS which are available at the Tampa bay area, probably because this area is prone to hurricanes and heavy rain/storm surges.

Real-time data on rainfall intensity and high-velocity winds can play a crucial role in warning communities about potential landslides and flooding. This allows for timely evacuations, prioritization of relief efforts, and ultimately, saving lives. It also allows preservation of valuable weather data of the region.

To maximize early warning systems, information from Automatic Weather Stations (AWS), satellite imagery, lightning reports from apps like Weatherbug and Damini, and even social media should be fully utilized. This is especially critical as climate change and warmer oceans are causing extreme weather events to become more intense, unpredictable, and accompanied by increased rainfall.

While I specifically mention DAVIS AWS, as we’ve successfully used this equipment for 6-7 years, there are undoubtedly many other reliable brands. The key requirement is that weather data must be available online with frequent updates.

For instance, the India Meteorological Department (IMD) has an AWS site that I found helpful during the 2024 monsoon season. However, the site’s updates are not as frequent, and parameters like rainfall intensity are missing. To address these gaps, private networks, such as the one in our region, can provide essential supplementary data.
STH strongly recommends building up on what is already available so as to make our early warning systems more robust and effective.

Praful Rao
SaveTheHills
savethehills@gmail.com
9475033744

Our adverse weather early warning work on What'sApp groups in the Darjeeling- SIkkim region: Thunderstorms of 11/12Apr2024 in Kalimpong

After the Teesta Valley GLOF of 04Oct2023, our region has been extraordinarily dry, with the erratic western disturbance activity in the winter months, robbing us of all our winter rain. In Kalimpong we had the first showers after Oct2023, between 19 & 27Mar2024 where we clocked 112.6mm. Thereafter, it has been dry with forest fires again starting in the Teesta Valley.
With regard to early warnings on adverse weather events and disbursement of information on landslides, road blocks etc, SaveTheHills has been running several very active and large What'sApp groups in the Darjeeling-Sikkim region called 'Hazard Alerts or HA' for many years now and the following cloud image on approaching adverse weather was posted in the group on 11Apr2024:

This image was posted on 'Hazard Alerts' WhatsApp group at 1.31pm on 11Apr2024 along with lightning warnings from the IMD 'Damini' (lightning warning) app. Shortly after this was done, the first storm hit our region at around 2.30pm. Wind speeds in gusts reached upto 58kmph.

This storm died down momentarily at around 4.30pm only to pick up again quickly. The following cloud image along with NOWCASTs from IMD were posted to members in the 'Hazard Alerts' What'sApp groups.

Warning posted at 5.36pm to our WhatsApp groups alerting them about another storm which was approaching.

Subsequent cloud images which show the progress of the storm from 6.45pm to 10.45pm on 11April2024

The thunderstorm which hit Kalimpong at 2.30pm on 11April2024, raged right thru the night and only ceased at around 8.00am on 12Apil2024. Surprisingly, we had only 2mm of rain however strong, gusty, westerly winds from Nepal along with lightning prevailed for more than 12hrs. The graphical analysis of the windspeed from our Davis Vantage Pro AWS is placed below:

Though there were no casualties or damage from the storm, what was unusual was its duration considering there was no major weather system (such as a depression/cyclone) near by.
Also what is possible today is to get reliable and accurate information of such weather events in advance and to disburse the same quickly to a large number of people. We have been doing this regularly in WhatsApp since Jun 2016.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya

Extraordinary high intensity and very localized rainfall of 29Aug2023 at Kalimpong

Meteorological conditions
28Aug2023 was a cloudy day and except for a little early morning rain, it was dry in Kalimpong. We even had a rare 'NO WARNING' for Sub-Himalayan West Bengal (SHWB) and Sikkim.

Cloud images showed fairly settled weather in our region through the day - even until 8.15pm on 28Aug2023, when I put a last post in 'Hazard Alerts' our What's App 'Early Warning' group in the Darj-Sikkim region.

                  Above image shows no major clouding in the area circled.

The clouding suddenly increased thereafter, as seen in the IR Image of 11.45pm of 28Aug2023:

              Notice the clouding which has suddenly appeared below Kalimpong

Nowcast issued by IMD is placed below

Rainfall of 29Aug2023 morning
We had sudden and very intense rainfall starting from 1.30am with peak intensities crossing 135mm/hr. The rainfall amount was 79.2mm in a very short time.

The screenshot of Damini (Lightning Alert app) showing no lightning at 3.06am in our area is below

And at 3.45am, with the rainfall declining over Kalimpong, the clouding vanished, just as quickly as it had appeared.

What is amazing in this event, besides the extremely sharp increase and decrease of rain intensity, is that it rained only over Kalimpong.
Adjoining towns of Darjeeling, Kurseong and Todey (where there are Davis automatic weather stations) had ZERO rainfall

QUESTION IS:
ARE WE PREPARED FOR THIS TYPE OF RAINFALL WHICH IS NO LONGER EXTRAORDINARY BUT BECOMING THE NEW NORMAL?

Praful Rao
Kalimpong district
Darjeeling-Kalimpong Himalaya
savethehills@gmail.com
9475033744

 

Heavy rains in the Darjeeling-Kalimpong region on 08/09Aug2023.

The meteorological conditions which led to the heavy rains are given below:

The satellite images of 08/09August2023 which were posted in our What's App group are shown:

In Kalimpong, the rains started at around 7pm and continued through the night even though the intensity was less around midnight. The rainfall intensity graph from a Davis Vantage Pro2 AWS at my home in Tirpai, Kalimpong is given below:

Unlike the localized rains of 01Aug2023, rainfall on 09Aug occurred over larger area  and included the towns of Darjeeling and Kurseong. The rainfall distribution map is given below:

The heavy rains 01Aug2023 (165.4mm) and that of 08Aug2023 (131.2mm) together add up to 296.6mm against a monthly rainfall in Aug of 495.2mm - as such we received 59.89% of our monthly rain in just two days.
Landslides
Landslides were reported in
Kalimpong - Echay bustee
Darjeeling - Rimbick
Darjeeling- Pul Bazar

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya
9475033744
savethehills@gmail.com

The deluge of Delhi (08Jul- 15Jul2023): some data, maps and images

Meteorological conditions

The meteorological conditions which caused the flooding of Delhi in 2023 between 08July till approximately 15July2023 have already been described in the previous blog - the same conditions which caused landslides and destruction in Himachal Pradesh resulted in parts of Delhi getting flooded by the Yamuna river.

As a matter of fact, large parts of Himachal and the foothills of Haryana and Punjab form the watershed area for the Yamuna river and much of the storm water from these areas finally drains into the Yamuna (see map below).

Rainfall from these catchment areas which eventually led to the flooding is as follows:

The average monthly rainfall for Delhi with other associated rainfall data is given below:

The actual rainfall

CM of Delhi, Arvind Kejriwal made a press statement saying that on 08/09Jul2023, Delhi had received 153mm of rain and the city's systems were "not designed to take such unprecedented rain", due to which major roads were submerged, traffic disrupted, and homes and businesses inundated.
According to officials, Delhi's outdated drainage system can handle only up to 50 mm of rainfall in 24 hours.

However, what became clear was it was not only climate change or the heavy rainfall which had caused the flooding in Delhi. It was also the release of Yamuna water from Hathnikund barrage in Haryana which caused the inordinate amounts of water to reach Delhi

Also involved was the water management of Yamuna river in the 22km that the river flowed thru Delhi. The 3 barrages which managed this is shown below

 

Flooded areas and satellite images
The areas which were flooded in early July 2023 were those in the vicinity of the Yamuna river in NE Delhi and also some areas for whom it was a grim first time - parts of Ring Road, Mathura road etc.
Planetscope Videos
ISBT, Kashmiri Gate, Delhi Jal Board Area

Yamuna Biodiversity Park Area

Images

We will keep updating these inputs in the future
Update on 09Aug2023

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya
savethehills@gmail.com
9475033744